Discuss the soil profile in detail and draw the diagram to show different layers of soil?
Soil is made up of different layers which constitute particles of different sizes. These different layers of soil form Soil Profile. The layers which form the soil profile are as follows:
- Top Soil: This forms the uppermost layer of the soil.Agricultural activities are carried out in this layer. This layer provides the essential nutrients to the plants and consists of tiny particles of sand, clay, humus moisture and air. Humus makes the soil fertile.
- Sub Soil: This is the second layer of soil and Contains water and air but very little Humus. Roots of big trees penetrates upto this layer.
- Bed Rock. This is the last layer of soil profile.inside the earth. It contains the big rocks and is deep inside the Earth.
Deforestation by humans is one of the main cause for soil erosion. Do you agree. Give reasons for your answer.
Answer: Yes, deforestation should be considered as one of the main cause for soil erosion. Human are cutting trees to fulfil their need for wood and need for spaces for construction of flats, cities , roads, factories etc. As trees and plants are cut down the uppermost layer of soil “Top Soil” loosens as the roots of plants and trees acts as soil binders. They hold the soil from eroding away by wind and water. In absence of these binders in the form of plants and trees the soil gets easioly carried away by wing and water which leads to Soil Erosion.
Give 5 reasons why Soil Erosion must be prevented?
Answer: The removal of fertile soil from top soil by various agents like, air, water or rain is called Soil Erosion. It must be prevented due to following reasons:
- The loss of fertile soil makes the land barren or unfit for farming and agriculture.
- Unfertile soil cannot grow forests and in turn reduces the rainfall in that area.
- Habitats of small animals like insects, rabbits, earthworms will be affected leading to their extinction.
- Soil erosion can also cause water pollution by dumping sediments, fertilizers, pesticides etc into rivers, lakes and water bodies. It can also lead to landslides in hilly areas as the removal of top soil can increase the slope steepness and reduces the friction in soil particles leading to loosened soil and risk of lad slide increases.
Describe the process of Soil Formation Or Write short note on “weathering”.
Answer: The process by which soil is formed due to the breakdown of rocks into smaller particles, which in turn is a result of repeated heating and cooling by the sun, wind and rain is called “Weathering”. The rain water gets trapped into the cracks of rocks or spaces between the rock particles. And when the trapped water cools, it expands, exerts pressure on the walls of the rock. When this process in continued over thousands of years, the rocks break into smaller pieces forming soil. So, formation of rocks or we can say weathering is a slow, long and continuous process.
Describe the process of Soil Formation Or Write short note on “weathering”.
Ans: The process by which soil is formed due to the breakdown of rocks into smaller particles, which in turn is a result of repeated heating and cooling by the sun, wind and rain is called “Weathering”. The rain water gets trapped into the cracks of rocks or spaces between the rock particles. And when the trapped water cools, it expands, exerts pressure on the walls of the rock. When this process in continued over thousands of years, the rocks break into smaller pieces forming soil. So, formation of rocks or we can say weathering is a slow, long and continuous process.
What would have happened if rocks had not broken into tiny pieces?
Answer : If rocks would have not broken in tiny pieces the soil would not been formed leading the land infertile and barren bed rock where no plants would have grown. In absence of soil , there would have been no plants , no water cycle , no climatic regulations and ultimately no life on Earth.
Define Hydroponics?
Answer: Hydroponics is growing of plants (especially vegetation and medicinal plants) in absence of soil. This is done by growing the plants in water enriched with required minerals. The roots are exposed to nutritious liquid and once roots are grown they are supported by gravels.
Why embankments are constructed on both sides of river?
Answer : Embankments can help to prevent soil erosion by preventing flooding of topsoil of the adjoining fields into the rivers. The rocks and stones present, slower down the speed of running water and prevent the top soil from flowing out.
Define Step Farming. Explain why is it done.
Answer : In hill slopes, farming is done by cutting steps in the fields. This is called terrace or Step farming. The flow of water in hilly areas is very rapid due to the slope and this speedy downward movement of water carries away the top soil easily and accumulates it in the plains. So to reduce the speed of running water the steps are made. This not only reduces the speed of running water but also helps in accumulating the soil eroded from one step to the next step.
Write the effects of Silting?
Answer: The soil carries away by river when it is flowing down , is deposited in large amount in plains. The deposition is called Silting. Over a period of time ,this deposited soil increases and may cause the river to change their path. This may cause flood in cities and villages and may cause loss of life and property. Soil erosion by running water has made the Chambal valley in Madhya Pradesh very unfit for cultivation.
